1. Field of the Invention
The present invention relates to a mounting structure for a battery and a fuel tank of a gasoline-electric hybrid vehicle, and particularly to a mounting structure that can be implemented even for a gasoline-electric hybrid vehicle having a propeller shaft, the mounting structure allowing the vehicle to provide a cabin and/or cargo space, to have the center of gravity at a low position, and to use parts commonly used in a gasoline engine vehicle.
2. Description of the Related Art
In a gasoline-electric hybrid vehicle, which uses both an engine and an electric motor for generating driving power, it is a challenge to ensure a space for mounting a fuel tank and a battery. Conventionally, there is known a structure in which a fuel tank is disposed below the rear seat similarly to a typical gasoline engine vehicle, and a battery is disposed on the back side of the rear seat or below the floor of a cargo space in the back of the rear seat. However, when a battery is disposed on the back side of the rear seat, the depth dimension of the cargo space is reduced, and thus seat arrangement such as a “trunk through” cannot be made by folding down the back rest of the rear seat. In the case where the battery is disposed under the floor of the cargo space, loading and unloading a cargo tends to be difficult due to the raised floor surface, and a sufficient height for a cargo cannot be ensured. In order to ensure the height for a cargo, a solution such as raising the floor surface of the trunk is necessary, and thus a significant restriction in design of a hybrid vehicle is imposed and it is difficult to ensure a driver's view at the same time. In addition, when the battery is disposed at one of the above-described positions, the center of gravity of the vehicle is raised, and thus the running stability of the vehicle is lowered.
On the other hand, there is also proposed a technology that disposes a battery, for example, in a center console in the cabin. In this case, however, a passenger space in the cabin and a storage space are sacrificed. In addition, in the consideration of safety in case of a collision, the battery is preferably disposed outside the cabin. There is also proposed a technology that disposes a battery under the floor panel of an electric vehicle driven only by an electric motor. For example, Japanese Unexamined Patent Application Publication (JP-A) No. 2000-247261 describes a vehicle body floor structure in which a center portion of the floor panel of the vehicle in the vehicle width direction is formed in a substantially hat shape, and a battery is installed below this projecting center portion.
The technology described in JP-A No. 2000-247261 cannot be applied to a four-wheel drive vehicle and a rear-wheel drive vehicle in which a propeller shaft is disposed at a center portion of the vehicle in the vehicle width direction. In addition, the technology described in JP-A No. 2000-247261 is directed to an electric vehicle, which is driven only by an electric motor, and does not consider a vehicle structure that has a fuel tank. Furthermore, in the case where a gasoline engine vehicle and a hybrid vehicle are produced as variations from a common platform, designing two types of floor panel separately increases the number of development steps and investment of production facility